Luxman R-600 (1973)

At 11kg and 50 watts per channel, it sits in the middle of 1970s Japanese high fidelity - solid-state power with careful engineering behind it.

Overview

The Luxman R-600 doesn't shout for attention. It has no glowing VU meters and no forest of sliders. Released in September 1973, this stereo integrated amplifier was the flagship of Luxman's 500 series, a line built around the company's core engineering values at the time. The 11kg weight points to heavy internal construction, and the spec sheet backs it up.

The first thing to notice is the symmetry. The main amplifier is a pure complementary circuit, fully direct-coupled across all stages, with NPN and PNP power transistors Darlington-connected in the Class B output stage. The transistors are matched in pairs for identical current amplification factor (hfe), so the positive and negative halves of the waveform balance. That kind of detail wasn't common in mass-market gear. It's what you'd expect from an engineer who cared about crossover distortion and transient response, not just wattage claims. The numbers hold up: 50W + 50W into 8 ohms with less than 0.03% THD at full power is impressive for 1973, and the damping factor is 40 across the audible band.

The preamplifier is just as deliberate. The phono equalization stage is a three-stage direct-coupled design - NPN, PNP, NPN - which gets rid of the coupling capacitors that can color the sound. RIAA curve deviation is held to ±0.5 dB. Ultra-low noise transistors are used throughout the preamp stages, for a signal-to-noise ratio of 80 dB or better on line inputs and 65 dB on phono. That's not class-leading by modern standards, but in 1973 it was competitive, especially for a unit with no exotic components or tube stages.

Input flexibility is solid for its era. Phono1 has switchable input impedance (50k, 65k, or 90k ohms), a rare feature that points to cartridge matching. Phono2, Tuner, Aux1, Aux2, and Mic inputs cover the usual source lineup of the early '70s. The tone controls use Luxman's proprietary LUX System NF Type with selectable bending points - low frequencies at 150, 300, or 600 Hz, highs at 1.5, 3, or 6 kHz - so voicing can be adjusted finely without the usual sonic cost of passive tone circuits. A low-cut filter at 30 Hz and a high-cut at 8 kHz (both 6dB/octave) handle room correction, and a dedicated 70 Hz low boost gives a gentle lift for under-damped systems.

One small detail is the muting circuit. It suppresses the thump at power-on and power-off. The power supply uses two 10,000 μF electrolytic capacitors for filtering, modest by today's standards but enough for the claimed 200W power consumption under full load. The preamp outputs deliver 580mV standard and up to 5V maximum, so the unit can drive external power amplifiers for bi-amping or system expansion.

Specifications

Key Features

Pure Complementary Direct-Coupled Amplifier Design

The main amplifier's pure complementary symmetry is a working feature, not a buzzword. Matched NPN and PNP transistors in a Darlington configuration share the same hfe, which minimizes crossover distortion and improves transient response. Direct coupling across all stages removes the phase shifts and frequency roll-off associated with coupling capacitors, and this adds to the wide bandwidth (5 Hz - 50 kHz). The topology was still relatively advanced in 1973, especially in an integrated unit.

Three-Stage Direct-Coupled Phono Equalizer

The phono stage uses a three-transistor direct-coupled design (NPN-PNP-NPN), which avoids the coloration and phase anomalies of capacitor-coupled stages. Combined with precise RIAA equalization (±0.5 dB deviation), the result is a clean, accurate phono response. The switchable input impedance on Phono1 allows tuning for different moving magnet cartridges, which suggests Luxman expected serious turntable use.

LUX System NF Type Tone Control with Bending Point Switching

The R-600's tone controls don't use a fixed shelving filter. They use Luxman's NF (Negative Feedback) system with selectable bending frequencies: 150, 300, or 600 Hz for bass and 1.5, 3, or 6 kHz for treble. That allows adaptation to room acoustics or speaker characteristics. This level of control was uncommon in integrated amps.

Ultra-Low Noise Preamplifier Stages

Noise performance was clearly a priority. Ultra-low noise transistors throughout the preamp section give a residual noise level of 0.5 mV or less and S/N ratios of 80 dB or better on line inputs. The 65 dB minimum on phono is modest by today's standards but was competitive for a solid-state design in 1973, and it was done without tube-based stages.

High Damping Factor and Stable Output

With a damping factor of 40 into 8 ohms across 20 Hz to 20 kHz, the R-600 keeps a firm grip on speaker cones, which helps dynamic drivers in particular. The 50W + 50W output into 8 ohms, verified at 0.03% THD, points to clean, stable power delivery, and the 200W power consumption under full load fits with that. The single-channel 60W rating hints at headroom for difficult loads or transient peaks.

Integrated Muting Circuit

The muting circuit suppresses turn-on and turn-off thumps. It protects the speakers and avoids the jarring noise common in amplifiers of the era.

Historical Context

eBay Listings

Black Aluminum Front Rear Footpegs for Suzuki GSX-R 600 750

$21.39

8-Speaker 600W UTV Sound bar Bluetooth Polaris ATV RZR Water

$208

As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.

Related Models

• Luxman R-5030
• Luxman RX-103 (1978)
• Luxman R-114 (1975)
• Luxman R-1500E (1975-1978)
• Luxman R-104 (1975)
• Marantz 2226 (1974-1976)
• Marantz 2226B (1979-1980)
• Marantz 2235 (1974-1977)
• Marantz 2238B (1978-1980)
• Marantz 2250B (1978-1980)